Takenoko is young bamboo shoot used in many spring dishes in Japan. Fresh young buds are in season in March to May in Japan. They need to be prepared quickly after being harvested to avoid the taste becoming harsh and bitter.
However, it is hard to get fresh Takenoko in the US. It is often sold precooked, ready to use, usually in a vacuum sealed package or canned. Precooked Takenoko is softer and a little less flavorful, but it is easy to use and is a good alternative to the fresh. It still can be used in dishes like Chikuzenni or mixed rice like Barazushi.